The present invention relates in general to strain relief clamps for securing electrical conductors and in particular to an improved frictional locking non-rotatable strain relief clamp for use with an electrical plug or socket. Typically, the wire ends of the electrical conductor are attached to the plug or socket assembly by means of screws. It is important to prevent the conductor from being pulled loose from the screws when a tension is applied to the conductor. Numerous types of strain relief clamps of varying complexity are found in the prior art to achieve this purpose.
U.S. Pat. No. 3,390,371 discloses a strain relief clamp for use with an electrical plug or socket. The strain relief clamp is best shown in FIG. 8 and comprises a support bracket and two cable clamps and is described in column 5, lines 55-75, and column 6, lines 1-60 of the specification. The two cable clamps slide onto the support bracket and are held in place by two screws which pass through openings in one cable clamp into threaded holes in the other cable clamp. The support bracket is attached to the plug or socket by a pair of screws. The clamp members comprise a hollow semi-circular shell with the addition of a wall and two grooves on one side of the hollow shell. The grooves align with flanges on the support bracket and hold the clamp sections in position.
The present invention is a novel improvement on the strain relief clamp as depicted in U.S. Pat. No. 3,390,371. In that patent the cable clamps disclosed require a large amount of nonmetallic material and are somewhat complex in structure. Also the disclosed strain relief clamp utilizes a metallic support bracket which is expensive. Because of the type of structure used, even if the metallic support bracket were designed using nonmetallic material, the support bracket would require a substantial amount of material.
U.S. Pat. No. 3,390,371 is the closest prior art of which applicant is aware, but applicant does not represent that a search has been made or that no better art exists. A concise explanation of the relevance of the patent has been given above and a copy of the patent is being submitted with this specification.
The relevance of the prior art indicated in the present specification should be not be given a limited interpretation. The prior art item may be found to have relevance in a passage other than the one referred to or to have relevance in a sense different than as stated.